API, originally Advanced Programming Interface but now more commonly known by its near synonym, Application Programming Interface, is any defined inter-program interface. API or api may also refer to: · Api , a mountain in Nepal · API gravity, a measure of the density of petroleum · Academic Performance Index · Academic Programs International · Active pharmaceutical ingredient · Advance Passenger Information · Air Pollution Index in Hong Kong · Alabama Polytechnic Institute · Alphabet phonétique international or International Phonetic Alphabet · American Petroleum Institute · Animal Protection Institute · Atmospheric pressure ionization · Australian Property Institute · Automated Processes Inc · Aviation Partners Inc. · Armor-piercing incendiary, a type of armor-piercing shot and shell · Asi